135 lines
4.2 KiB
C
135 lines
4.2 KiB
C
/* Suspend until termination of a requests.
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Copyright (C) 1997, 1998, 1999 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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/* We use an UGLY hack to prevent gcc from finding us cheating. The
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implementation of aio_suspend and aio_suspend64 are identical and so
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we want to avoid code duplication by using aliases. But gcc sees
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the different parameter lists and prints a warning. We define here
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a function so that aio_suspend64 has no prototype. */
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#define aio_suspend64 XXX
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#include <aio.h>
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/* And undo the hack. */
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#undef aio_suspend64
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#include <errno.h>
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#include <stdlib.h>
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#include "aio_misc.h"
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int
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aio_suspend (list, nent, timeout)
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const struct aiocb *const list[];
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int nent;
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const struct timespec *timeout;
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{
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struct waitlist waitlist[nent];
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struct requestlist *requestlist[nent];
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pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
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int cnt;
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int result = 0;
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int dummy;
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int none = 1;
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/* Request the mutex. */
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pthread_mutex_lock (&__aio_requests_mutex);
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/* There is not yet a finished request. Signal the request that
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we are working for it. */
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for (cnt = 0; cnt < nent; ++cnt)
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if (list[cnt] != NULL && list[cnt]->__error_code == EINPROGRESS)
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{
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requestlist[cnt] = __aio_find_req ((aiocb_union *) list[cnt]);
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if (requestlist[cnt] != NULL)
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{
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waitlist[cnt].cond = &cond;
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waitlist[cnt].next = requestlist[cnt]->waiting;
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waitlist[cnt].counterp = &dummy;
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waitlist[cnt].sigevp = NULL;
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waitlist[cnt].caller_pid = 0; /* Not needed. */
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requestlist[cnt]->waiting = &waitlist[cnt];
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none = 0;
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}
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}
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/* If there is a not finished request wait for it. */
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if (!none)
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{
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int oldstate;
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/* Since `pthread_cond_wait'/`pthread_cond_timedwait' are cancelation
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points we must be careful. We added entries to the waiting lists
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which we must remove. So defer cancelation for now. */
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pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &oldstate);
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if (timeout == NULL)
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result = pthread_cond_wait (&cond, &__aio_requests_mutex);
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else
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result = pthread_cond_timedwait (&cond, &__aio_requests_mutex,
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timeout);
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/* Now remove the entry in the waiting list for all requests
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which didn't terminate. */
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for (cnt = 0; cnt < nent; ++cnt)
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if (list[cnt] != NULL && list[cnt]->__error_code == EINPROGRESS
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&& requestlist[cnt] != NULL)
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{
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struct waitlist **listp = &requestlist[cnt]->waiting;
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/* There is the chance that we cannot find our entry anymore.
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This could happen if the request terminated and restarted
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again. */
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while (*listp != NULL && *listp != &waitlist[cnt])
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listp = &(*listp)->next;
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if (*listp != NULL)
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*listp = (*listp)->next;
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}
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/* Now it's time to restore the cancelation state. */
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pthread_setcancelstate (oldstate, NULL);
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/* Release the conditional variable. */
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if (pthread_cond_destroy (&cond) != 0)
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/* This must never happen. */
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abort ();
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if (result != 0)
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{
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/* An error occurred. Possibly it's EINTR. We have to translate
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the timeout error report of `pthread_cond_timedwait' to the
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form expected from `aio_suspend'. */
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if (result == ETIMEDOUT)
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__set_errno (EAGAIN);
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result = -1;
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}
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}
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/* Release the mutex. */
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pthread_mutex_unlock (&__aio_requests_mutex);
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return result;
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}
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weak_alias (aio_suspend, aio_suspend64)
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